1. Technical Field
The present invention relates to a projector provided with a light blocking member for controlling an amount of illumination light.
2. Related Art
As a projector using a light blocking member, there is known a projector having a pair of light blocking members, which can be opened and closed by rotation, disposed between a pair of lens arrays in a illumination device so as to be symmetrical about the illumination light axis, thereby controlling an amount of blocking of the illumination light (see, e.g., JP-A-2007-71913). In such a projector, both of the extension lines of a pair of rotational shafts (rotational support shafts) for rotatably supporting a pair light blocking members pass through the outside of the light path of the illumination light, and the tips of the pair of light blocking members are located on the side opposite to the side of the extension lines of the rotational shafts, namely the side of the center of the illumination light beam. Since the tips of the light blocking members move closer to and away from each other across the light axis of the illumination light by rotating the tips of the pair of light blocking members around the rotational shafts, the amount of blocking of the illumination light can be controlled (see the document mentioned above).
However, according to the light blocking members having the structure described above, since the closer to the tips of the light blocking members a portion thereof is located, the closer to the center of the illumination light the portion is located, the closer to the tips of the light blocking members the portion thereof is located, the more heat the portion absorbs. Therefore, since the light blocking members are apt to expand toward the tips thereof, and an amount of gap in the maximum blocking state of the illumination light is reduced with heating, accuracy in controlling the amount of blocking of the illumination light is lacking, and therefore, a variation might be caused in the dynamic contrast ratio.